Effect of Change in Total Cholesterol Levels on Cardiovascular Disease Among Young Adults

BACKGROUND: Although high serum cholesterol in young adults is known to be a predictor for cardiovascular events, there is not enough evidence for the association of cholesterol level change with cardiovascular disease (CVD). This study aimed to evaluate whether the change in cholesterol is associated with incidence of CVD among young adults. METHODS AND RESULTS: We examined 2 682 045 young adults (aged 20–39 years) who had undergone 2 consecutive national health check‐ups provided by Korean National Health Insurance Service between 2002 and 2005. Cholesterol levels were classified into low (<180 mg/dL), middle (180–240 mg/dL) and high (≥240 mg/dL). CVD events were defined as ≥2 days hospitalization attributable to CVD for 10 years follow‐up. Increased cholesterol levels were significantly associated with elevated ischemic heart disease risk (adjusted hazard ration [aHR]=1.21; 95% confidence interval [CI]=1.03–1.42 in low‐high group and aHR=1.21; 95% CI=1.15–1.27 in middle‐high group) and cerebrovascular disease (CEVD) risk (aHR=1.24; 95% CI=1.05–1.47 in low‐high group and aHR=1.09; 95% CI=1.02–1.16 in middle‐high group). Decreased cholesterol levels were associated with reduced ischemic heart disease risk (aHR=0.91; 95% CI=0.88–0.95 in middle‐low group, aHR=0.65; 95% CI=0.56–0.75 in high‐low group and aHR=0.68; 95% CI=0.65–0.73 in high‐middle group). Furthermore, lower cerebrovascular disease risk (aHR=0.76; 95% CI=0.62–0.92) was observed in the high‐low group compared with patients with sustained high cholesterol. CONCLUSIONS: The findings of our study indicate that increased cholesterol levels were associated with high CVD risk in young adults. Furthermore, young adults with decreased cholesterol levels had reduced risk for CVD.